Superior Court Judge Mary Jacobson during oral arguments on Aug. 15. ON Thursday she denied a stay on permitting same-sex marriages in New Jersey.

A New Jersey superior court judge on Thursday denied Gov. Chris Christie’s bid to put a hold on gay marriage in the state, meaning same-sex couples could begin to apply for marriage licenses as soon as Oct. 21.

The state, however, said in response that it would appeal the judge’s decision to deny its request for a stay on the appellate level. “The state will proceed to the next step by seeking a stay from the Appellate Division,” said a spokesman for the New Jersey Attorney General’s office, which represents the Christie administration in the matter.

The state must file its appeal of the stay by Oct. 11, and the plaintiffs must be notified by Oct. 15, according to a court schedule.

The state has already filed briefs arguing against same-sex nuptials to the appellate division and the New Jersey Supreme Court.

“This is wonderful news,” said Hayley Gorenberg, deputy legal director of Lambda Legal, the national organization that has argued a case seeking gay marriage in New Jersey. “The court’s decision once again confirms that the hardships of not being able to marry are real and immediate.”

A spokesman for Mr. Christie declined to comment on the decision Thursday, and referred to the governor’s comments on gay marriage from his campaign debate Tuesday.

“I believe that the institution of marriage for 2,000 years is between a man and a woman, and if we’re going to change that core definition of marriage, I don’t think that should be decided by 121 politicians in Trenton or seven judges on the Supreme Court,” he said.

Mr. Christie vetoed a bill last year that would have allowed for same-sex marriage, arguing that voters should decide on the issue. The Republican governor supports the state’s existing civil unions, which provide all the New Jersey benefits of marriage.

In 2011, Lambda Legal and its co-counsel filed a lawsuit asking for gay marriage on behalf of six New Jersey couples and their children. The plaintiffs asked for a decision on the case in June in the wake of the U.S. Supreme Court striking down the Defense of Marriage Act, which had barred federal benefits to married same-sex couples.

Last month, Ms. Jacobson ruled that gay marriage should be allowed, and gave the state until Oct. 21 to begin granting marriage licenses or appeal.

The state filed an appeal earlier this month and asked for a stay on the marriages until its case could wind its way through the courts. The Christie administration is expected to ask the New Jersey’s highest court to eventually rule on whether to allow same-sex marriage in New Jersey.

In her 17-page opinion issued Thursday afternoon, Ms. Jacobson said that the state’s appeal doesn’t have a “likelihood of succeeding” and didn’t adequately demonstrate that New Jersey would be harmed if marriages were allowed.

“Plaintiffs would suffer many hardships of constitutional magnitude if the stay were to be issued,” Ms. Jacobson wrote.

Thirteen states and Washington D.C. now permit gay marriage. All the states north of Maryland on the East Coast other than New Jersey allow for same-sex nuptials.